Scavenge pump



June 13, 1950 ML. EDWARDS SCAVENGE PUMP 2 Sheets-Sheet 1 Filed April 5, 1944 INVENTOR.

LOWELL [am 5 June 1950 M. EDWARD SGAVENGE PUMP 2 Sheets-Sheet 2 Filed April 3, 1944 Patented June 13, 1950 UNITED STATES PATENT OFFlCE 9 Claims.

This invention relates to pumps, and has particular reference to that class of pumps which are used for separating the component parts of an aerated liquid and for pumping the liquid component to a place of use. The invention is especially useful when embodied in a pump of the type used to return oil from the sump of an internal combustion engine housing to a source of oil supply.

The drawings illustrate the invention as embodied in a pump adapted to be mounted on the housing of an internal combustion engine in such position that the oil flows from the housing into the fluid inlet of the pump. The oil delivered to an internal combustion engine becomes aerated by reason of the churning action of the engine parts, and while the engine is operating an admixture of air and oil enters the intake port of the pump. At times the fluid entering the pump may be composed chiefly of oil, this being particularly true of those periods of operation immediately following starting the engine. When the engine is idle the oil drains from the engine parts into the lower portion of the housing where it collects until such time as the pump is energized to return the oil to the source of supply. At other times considerable quantities of air may enter the pump, either as free air or entrained with the oil being pumped. It is the purpose of the invention to provide a mechanism wherein the oil being pumped is also subjected to a centrifuging action for freeing the oil from the air entrained therein, and for returning the solid oil to the source of supply.

A device embodying the invention may comprise a casing having mounted therewithin a pump impeller and turbine runner comprising a fluid coupling, together with a second impeller comprising a centrifugal separating means. The first impeller is designed to impart to the liquid entering the casing both an axial flow for creating a slight inlet pressure at the pump which returns the oil to the storage tanks, and a torsional flow for transmitting a part of the power created by operation of the impeller to the turbine runner. The urbine runner is so designed as to develop a hydraulic reaction to the torsional flow of the liquid discharged from the first impeller, whereby the flow energy created by the impeller is transmitted as torque for driving a pump operatively connected to the turbine runner and also housed within the pump casing for returning the oil to the oil storage tanks. This pump, being driven solely by the power transmitted through the fluid coupling, delivers oil away from the unit in direct proportion to the amount of oil entering the intake port. A second impeller mounted in the fluid circuit on the discharge side of the turbine runner functions as a centrifugal separating means for separating the air from the liquid component of the oil, and discharges the oil into a collection chamber from whence it flows to the intake for the pump which functions to return the oil to the oil storage tank. The air is conducted away from the pump by way of port means which may return the air to the housing of the internal combustion engine.

It is an object of the invention to provide pumping means embodying a centrifuge for separating the gaseous and liquid components of fluid being pumped, and pumping means for delivering the liquid component of the fluid away from the unit in direct proportion to the amount of liquid entering the unit.

It is a further object of the invention to provide a scavenge pump embodying pumping means for delivering liquid away from the unit, a fluid coupling for driving said pumping means, and a centrifuge for separating the air from liquid entering the scavenge pump and delivering the airfree liquid to the pumping means.

It is a further object of the invention to provide a lubricating oil scavenge pump for an internal combustion engine having means for centrifuging the oil separating air from the oil, and having means for discharging the air from the pump and for returning the oil to the place of use or storage.

It is a further object of the invention to provide a pump for handling admixtures of gases and liquids and having means for centrifuging the fluids entering the pump for separating the gases from the liquid, and having means for discharging the gases from the pump and for delivering the liquid away from the pump to a place of use or storage.

The drawings illustrate the invention as embodied in a scavenge pump for an internal combustion engine. It is to be understood, however, that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various Ways. The terminology employed herein is for the purpose of description and not of limitation, it being understood that various changes in form, proportion, size and details of construction within the scope of the claims may be resorted to without departing from the spirit 3 or sacrificing any of the advantages of the invention.

In the drawings: Figure 1 is a longitudinal sectional perspective view of a pump embodying the invention; Figure 2 is a longitudinal sectional elevation of the pump shown in Figure 1; Figure 3 is a sectional view taken on the line 3-3 of Figure 2, showing the configuration of the blades of the several impellers and turbine runner; Figure 4 is a sectional elevation taken transversely of the pump on the line 4-4 of Figure 2; and Figure 5 is a sectional elevation taken on the line 55 of Figure 2, showing the construction of the displacement pump.

Considered briefly, a device embodying the invention may comprise a casing ID of generally cylindrical shape having end walls II and I2. The end wall II comprises the mounting for a motor 9 or other driving mechanism. In certain adaptations of the invention the device may be driven through a suitable driving connection with the internal combustion engine with which the device is associated, while in other adaptations it may be preferred to mount an electric motor 9 in the bell mounting I3, an armature shaft being shown by broken lines I4. At the opposite end of the casing I6 a transverse wall I5 divides the casing to form with the end Wall [2 and peripheral wall IS the working chambers of a displacement pump presently to be described.

Adjacent the end wall II the peripheral wall of the casing is interrupted to form an intake port 24, a discharge port 25 being positioned adjacent the transverse wall I5. In the event the device is employed as a scavenge pump for an internal combustion engine, the casing II] may be fastened to the engine housing (not shown) by screws which extend through the flanges 20 on the intake and discharge port members and engage in tapped recesses in mounting rings mounted on the flanges of registering ports in the engine housing. Between the intake and discharge ports is formed a chamber 26 within which is mounted mechanism comprising an axial flow pump, a fluid coupling, and centrifugal separating means. This structure together with the sump of the engine housing comprises a fluid circuit.

Extending longitudinally of the casing ID are axially aligned driving and driven shafts I1 and I8, respectively, the drive shaft I1 extending through the end wall I I for connection with the prime mover element. The shaft opening in end wall II is provided with a stuffing box I9 of conventional design. The driven shaft I8 is journaled in bearings 2| carried by the end Wall I2 and in bearings 22 carried by the transverse wall I5, the inner end of the shaft I8 being journaled in bearings 23 recessed in an enlarged end portion of the drive shaft I1 so that there may exist a differential speed of rotation between the two shafts.

Afiixed to the drive shaft I1 adjacent the intake port 24 is an axial flow pump impeller 21 comprising impeller blades 28 so formed as to impart both an axial flow and a torsional flow to the liquid entering the pump. The contour of the impeller blades 28 may be as best shown in Figure 3 wherein it will be seen that at the inlet end of the impeller each blade is pitched in the manner of a screw propeller and then curves in the direction of a plane intersecting with and parallel to the axis of rotation. In the vertical plane each impeller blade extends radially of the 4 shaft I1. The blades 28 may, as shown in the drawings, be formed integrally with the shaft I1 and with a cylindrical shroud 29 having close running clearance with the wall of the chamber 26.

A turbine runner 3| is mounted in the chamber 26 for receiving fluid delivered from the pump impeller 21. The turbine runner comprises turbine blades 32 affixed to a hub 33 keyed to the shaft I8. The blades 32 are so formed as to develop a hydraulic reaction to the torsional flow of the fluid leaving the impeller 21 whereby torque is transmitted to drive the shaft I8.

Also mounted in the chamber 26 is an impeller 36 having mechanical connection with the pump impeller 21 by means of a cylindrical member 31 comprising an extension of the shroud 29. Thus the impeller 36 is driven by the prime mover element at the speed of the drive shaft I1. The impeller 36 comprises radial blades 38 affixed at their outer edges to the cylindrical member 31 and at their inner edges to a hub 39. The hub 39 surrounds and is concentric with the shaft IS. The hub is supported out of contact with the shaft, being journaled at one end in a bearing 4| mounted in a cylindrical flange 42 extending axially from the transverse wall I5 and is supported at its opposite end by means of the impeller blades 38, cylindrical member 31 and shroud 29. Accordingly, th hub 39 is freely r0- tatable relative to and independently of the shaft I8. Thus the impeller 36 is rotatably supported at its inlet end by the cylindrical member 31 secured to the shroud 29 and at its discharge end by the bearing M which supports the hub 39.

It will be noted that the cylindrical member 31 does not extend the full length of the impeller 36, provision being made for peripheral discharge of fluid from the impeller 36 into a collection chamber 43 surrounding the impeller adjacent its discharge end. The collection chamber 43 is defined in part by the peripheral wall I 6 and in part by a Wall portion 44 which extends a short distance over the end of the impeller 36, and receives liquid flowing from between the impeller blades 38. The wall 44 is interrupted to form a port 50 surrounding the hub 39 through which the gaseous component of the fluid may flow from the area adjacent the hub of impeller 36 into the passage 45 communicating with the discharge port 25. The collection chamber 43 communicates by Way of passage 48 with the inlet chamber 49 of the gear pump 35.

The gear pump 35 comprises the driving gear 34 keyed to the shaft I8 and idler gear 46 mounted on stub shaft 41, the two gears having close running clearance with casing wall I6 to form an inlet chamber 49 into which liquid is delivered from the collection chamber 43 and a discharge chamber 5| from which liquid is delivered by way of discharge port 52.

In operation, an aerated fluid such as an admixture of oil and air enters the intake port 24 and flows into the inlet end of pump impeller 21, being there acted upon by the blades 28. As has been stated, the axial flow impeller functions both to move the fluid through the chamber 26 and to produce torsional movement to the liquid for driving the turbine runner 3 I The blades 32 of turbine runner 3| are curved to develop a hydraulic reaction to the torsional flow of fluid leaving impeller 21 whereby torque is transmitted to drive the shaft I8 and the gear 34 of gear pump 35. The pump impeller 21 is driven at motor speed, whereas the speed of shaft [8 will vary in proportion to the quantity of oil entering the pump through intake port 24. If this supply of oil is large the displacement pump will be driven at its maximum speed and the maximum quantity of solid oil will be delivered by the displacement pump through discharge port '52. In the event the supply of oil is diminished and an admixture of oil and air enters the intake port 24, the weight of the fluid present in the chamber 26 is reduced in proportion to the amount of air entrained with the liquid, and the amount of torque transmitted to the shaft I8 is correspondingly lessened. The speed of rotation of the turbine runner 3 I, therefore, and consequently of the shaft I8, is in direct proportion to the amount of oil entering the intake port. Since the displacement pump will deliver oil in direct proportion to the speed at which it is driven, it follows as a matter of course that the quantity of oil delivered from discharge port 52 is likewise in direct proportion to the amount of oil entering the intake port 24. The oil discharged from the turbine runner 3| is centrifuged in impeller 35, allowing only solid oil to enter passage 48, the air flowin through port 56 and passage 45, and being discharged from the pump through port 25.

In the impeller 36 the blades 38 function to produce a centrifugal separation of the component parts of the fluid entering the pump- The liquid component of the fluid is discharged centrifugally into the collection chamber 43 and flows from thence through passage 48 into the inlet chamber 49 of the gear pump. The gaseous component of the fluid, being forced to the center of rotation, flows along the hub 39 through port 55) and is expelled from the pump through discharge passage 45 and discharge port 25.

The device illustrated in the drawings has been designed for use as a scavenge pump for internal combustion engines in installations where the lubricating oil storage is at a point remote from the engine. For example, aircraft engines are lubricated by a pressure system which delivers oil from an oil storage tank through suitable conduits to the engine bearings. The oil drains .rom the bearings into the lower portion of the engine housing and from thence is returned to the storage tank by a scavenge pump. When the engine stops, oil collects in the lower portion of the engine housing in considerable quantities, and must quickly be removed therefrom at the time of starting the engine. For this reason, scavenge pumps usually are of greater capacity than needed for normal operation, since the quantity of oil to be returned to the storage tank during operation of the engine is considerably less than that which must be handled at the initial starting period. Moreover, during operation of the scavenge pump considerable quantities of air are delivered to the oil storage tank with the returned oil which tends to aerate the oil. Under conditions of flight at high altitudes the aerated oil tends to foam, and the oil lines may become air bound except that some means, such as the structure herein disclosed and described, is provided for relieving the oil of the entrained air.

It will be appreciated that the present device, when operating as a scavenge pump, provides means for producing centrifugal separation of the component parts of aerated fluid and, at the same time, functions as a pump means for returning the oil to the storage tank. Other uses for apparatus embodying the invention may be cited, such as the pumping of milk, or other highly aerated or gas bearing liquids, in the handling of which it is important that the gaseous component be separated from the liquid.

In the structure herein illustrated and described, the pump which returns the solid oil to the storage tanks is disclosed and described as a displacement pump of the type employing gears for pumping the liquid. In a modified construction a centrifugal pump impeller may be substituted for the gears 34 and 46 in a construction embodying a volute chamber and a peripheral discharge port, and wherein the centrifugal impeller is aflixed to the shaft l8 and is driven by the torque transmitted by the fluid coupling comprising the impeller 21 and turbine runner 3|. Moreover, the device will function as effectively if the oil pump were housed in a separate casing and the driving connection between the turbine runner and the oil pump comprised other power transmitting means than as herein illustrated and described. Therefore, having described one embodiment of the invention and the manner of its use, it will be apparent that modifications thereof will occur to those called upon to adapt the invention to other fields of utility, and it is my intention that this disclosure shall be considered as illustrative only and that the invention shall not be limited except as required by the prior art and as stated in the appended claims.

Having now described my invention and in what manner the same may be used, what I claim as new and desire to protect by Letters Patent is:

1. An apparatus for centrifuging admixtures of liquid and gaseous fluids and for pumping the liquid component of said fluids, comprising 3, casing having a fluid inlet, an impeller and a turbine runner mounted in said casing and defining a fluid coupling, a displacement pump mounted in said casing, means comprising said impeller for delivering liquid to said pump, driving means interconnecting said displacement pump and said turbine runner, centrifugal separating means mounted in said casing, driving means interconnecting said impeller and said centrifugal separating means, a passageway for conducting the liquid component of said fluid to said. displacement pump, and a discharge port communicating with said centrifugal separating means for the gaseous component of said fluid.

2. An apparatus for centrifuging admixtures of liquid and gaseous fluids and for pumping the liquid component of said fluids, comprising a casing having a fluid inlet, a plurality of impellers mounted in said casing, a turbine runner mounted in said casing, one of said impellers and said turbine runner comprising a fluid coupling, means for driving said impellers, a displacement pump mounted in said casing, driving means connecting said turbine runner and said displacement pump, one of said impellers comprising a centrifuge for producing centrifugal separation of the component parts of said fluid, port means for conducting the liquid component of said fluid from said centrifuge to said displacement pump, and port means for the gaseous component of said fluid.

3. An apparatus for centrifuging admixtures of liquid and gaseous fluids and for pumping the liquid component of said fluids, comprising a casing having a fluid inlet, a fluid coupling mounted in said casing comprising a pump impeller and a turbine runner, a pump, driving means interconnecting said turbine runner and said pump, centrifugal separating means mounted in said casing on the discharge side of said turbine runner for producing centrifugal separation of the liquid and gaseous components of said fluid, means for conducting the liquid component from said centrifugal separating means to said pump, and a discharge port in said casing for the gaseous component of said fluids.

4. An apparatus for centrifuging admixtures of liquid and gaseous fluids and for pumping the liquid component of the said fluids, comprising a casing having a fluid inlet, a plurality of impellers mounted within said casing, a turbine runner mounted in said casing between said impellers, a displacement pump, driving means connecting said turbine runner and said displacement pump, at least one of said impellers comprising centrifugal separating means for separating the gaseous and liquid components of said fluid, and means for conducting the liquid component of said fluid from said separating means to said displacement pump.

5. An apparatus for centrifuging admixtures of liquid and gaseous fluids and for pumping the liquid component of said fluids, comprising a casing having a fluid inlet, an impeller and a turbine runner mounted in said casing and defining a fluid coupling, a pump mounted in said casing for delivering liquid away from said apparatus, driving means interconnecting said pump and said turbine runner, centrifugal separating means mounted in said casing, driving means interconnecting said impeller and said centrifugal separating means, means comprising said impeller for delivering liquid to said pump, a passageway for conducting the liquid component of said fluid to said pump, and a discharge port communicating with said centrifugal separating means for the gaseous component of said fluid.

6. An apparatus for centrifuging admixtures of liquid and gaseous fluids and for pumping the liquid component of said fluids, comprising a casing having a fluid inlet, a displacement pump for delivering liquid away from said apparatus, an impeller for delivering liquid to said displacement pump, a turbine runner, said impeller and said turbine runner comprising a fluid coupling, means interconnecting said turbine runner and said displacement pump whereby said displacement pump is driven by said fluid coupling, an air-oil separating means arranged to receive fluid from said impeller for separating the gaseous and liquid components of said fluid, a discharge port for the gaseous component of said fluid, and means for conducting the liquid component of said fluid from said separating means to said displacement pump.

7. An apparatus for centrifuging admixtures of liquid and gaseous fluids and for pumping the liquid component of said fluids, comprising a casing having a fluid inlet, a pump for delivering liquid away from said apparatus, an impeller for delivering liquid to said pump, a turbine runner, said impeller and said turbine runner comprising a fluid coupling, means interconnecting said turbine runner and said pump whereby said pump is driven by said fluid coupling, an air-oil separating means arranged to receive fluid from said impeller for separating the gaseous and liquid components of said fluid, a discharge port for the gaseous component of said fluid, and means for conducting the liquid component of said fluid from said separating means to said pump.

8. An apparatus for scavenging admixtures of liquid and gaseous fluids comprising a casing having an inlet, pump means for delivering liquid away from said apparatus, an impeller mounted in said casing for delivering liquid to said pump means, a turbine runner, said impeller and said turbine runner comprising a fluid coupling, means interconnecting said turbine runner and said pump means whereby said pump means is driven by said fluid coupling, said impeller having means associated therewith and driven thereby for separating from said liquid gases occluded therein and means for conducting liquid from said separating means to said pump means.

9. An apparatus for scavenging admixtures of liquid and gaseous fluids comprising a casing having an inlet, pump means for delivering liquid away from said apparatus, an impeller mounted in said casing for delivering liquid to said pump means, a turbine runner, said impeller and said turbine runner comprising a fluid coupling, means interconnecting said turbine runner and said pump means whereby said pump means is driven by said fluid coupling, means for separating from said liquid gases occluded therein, and means for conducting liquid from said separating means to said pump.

MILES LOWELL EDWARDS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,092,092 Sinclair Sept. 7, 1937 2,107,035 Hall Feb. 1, 1938 2,160,295 Stewart May 30, 1939 2,285,169 Pyle June 2, 1942 2,322,568 DeLancey June 22, 1943 2,340,975 Morgan Feb. 8, 1944 2,358,629 DeLancey Sept. 19, 1944 2,416,193 Meyers Feb. 18, 1947 FOREIGN PATENTS Number Country Date 251,237 Great Britain 1926 374,636 Great Britain 1932 

